The present invention is directed to a new method for stabilizing hydrogen peroxide solutions. The invention is particularly directed to the provision of various types of pharmaceutical compositions containing stabilized hydrogen peroxide at relatively low concentrations, such as ophthalmic, otic, nasal and dermatological compositions. The invention is especially useful in the fields of hydrogen peroxide solutions for disinfecting contact lenses and ophthalmic compositions that contain very low concentrations of hydrogen peroxide as an antimicrobial preservative.
Hydrogen peroxide is inherently unstable in aqueous solutions due to its susceptibility to decomposition by trace levels of transition metal ions in solution. These ions serve as catalysts to the decomposition of hydrogen peroxide into oxygen and water.
In order to address this stability problem, it is necessary to include a stabilizing agent in hydrogen peroxide solutions. Examples of such stabilizing agents include: phosphonates, such as those sold under the name “DEQUEST” (a trademark of Monsanto); sodium thiosulfate; and sodium stannate. The use of phosphonates to stabilize hydrogen peroxide in ophthalmic compositions is described in U.S. Pat. No. 5,725,887.
The use of inorganic nanoparticles as carriers for biocides in ophthalmic compositions is described in International (PCT) Publication No. WO 03/059193.